The present invention relates generally to automated fastening equipment and more particularly to equipment that automatically delivers fasteners to a work station or a plurality thereof.
Manufacturing equipment that automatically delivers fasteners to a workpiece, or a fastening device, is typically employed in high rate production environments. The equipment generally comprises a storage device for the fasteners and a mechanism or system that transports fasteners from the storage device to the workpiece or fastening device. For example, U.S. Pat. No. 5,588,554 to Jones, the contents of which are incorporated herein by reference in their entirety, discloses a device for delivering fasteners to a workpiece comprising a suction head that removes fasteners from a storage area and delivers the fasteners through a delivery tube using a vacuum. The fasteners are individually stored in holes of a predetermined or fixed depth, and only one fastener may be stored in any given hole. Accordingly, each hole contains a fastener of a specific configuration, diameter, and grip length. Moreover, the device of Jones is incorporated in a relatively large assembly system that is permanently installed at a fixed location within a production facility, and thus the fastener delivery system is not portable.
Yet another known art fastener delivery system is disclosed in U.S. Pat. No. 5,193,717 to Rink et al., wherein rivet cartridges are unloaded and rivets are delivered to a rivet machine or the like with pressurized air. The rivet cartridges are filled off line by a rivet pump that receives rivets from a vibrating bowl feeder, and the fasteners are delivered through a common passageway to a fastener installation tool. However, the fastener delivery system of Rink et al. requires a separate fastener escapement mechanism to remove and deliver the fasteners. Additionally, the fastener delivery system of Rink is mounted to a fixed base plate and is therefore not mobile or portable.
Unfortunately, automated fastener delivery equipment of the known art is substantially large in size and must be permanently installed into the flooring and existing structure of a manufacturing facility. U.S. Pat. No. 5,664,311 to Banks et al., the contents of which are incorporated herein by reference in their entirety, illustrates such an automated fastening system wherein a large assembly jig is mounted to a floor and consumes a substantial volume within a manufacturing facility. Furthermore, the parts or components that are being assembled must be positioned with tooling located within a working envelope of the automated fastener delivery equipment, which may also consume a substantial volume. Accordingly, the automated fastener delivery equipment of the known art is not portable and cannot be moved from work station to work station in order to deliver fasteners to a variety of assemblies and subassemblies.
In the production assembly of aircraft, the majority of substructure such as fuselage frames and longerons, along with wing spars and ribs, are joined to the skin of the aircraft with thousands of fasteners. Further, a plurality of fastener types, along with variations in diameters and grip lengths, are typically used in an aircraft assembly or subassembly. (Generally, a fastener grip length refers to the cumulative thickness of the parts that the fastener holds together). Moreover, a majority of the substructure parts are manually assembled and are not assembled using automated fastening equipment.
During manual assembly operations, an operator must first determine the appropriate fastener type and diameter from a blueprint or other manufacturing work instruction delivery system. Due to manufacturing variations in individual part fabrication and assembly positioning variations, the proper grip length of the fastener is often determined by manually measuring hole depths. Once the proper fastener configuration is determined, the fastener stock must then be located and selected from fastener bins, which are typically stored at a common location near the work station. A limited number of fasteners are then moved by hand from the fastener bins to the work station and are generally staged within the reach of an operator. If permitted by the work environment, several fasteners are stored in a pouch that is secured around the waist of an operator. Accordingly, the operator sorts through the fasteners to select the proper configuration and inserts the fastener directly into a hole through the parts or inserts the fastener into an installation tool that installs the fastener through the parts.
As a result, a significant amount of time is spent by an operator determining the proper fastener configuration, locating the fastener within a storage bin, and transporting the fastener to the work station for installation. In addition, the manual location and staging of fasteners introduces an increased risk of foreign object damage (FOD) from a dropped or misplaced fastener, which may result in severe damage to and/or inoperation of certain aircraft systems. Therefore, manual fastener installation procedures are time consuming and may also increase the risk of failure of aircraft systems.
Accordingly, a need remains in the art for an automated fastener delivery system that is portable and which efficiently delivers fasteners to at least one work station where parts are being manually assembled. The portable fastener delivery system should be capable of delivering a plurality of different fastener configurations, moreover to a plurality of work stations. The portable fastener delivery system should further be capable of automatically selecting the proper fastener configuration from a variety of inputs and should also be capable of maintaining a record of fastener inventory that is further integrated with existing production manufacturing systems.
In one preferred form, the present invention provides a portable fastener delivery system that comprises an unloading mechanism in communication with a fastener storage device, wherein a control system activates the unloading mechanism to remove a specific fastener configuration from the fastener storage device and transport the fastener to a delivery conduit, where the fastener is caused to be delivered to a work station. Generally, the unloading mechanism, fastener storage device, control system, and delivery conduit are disposed within a portable platform such as a mobile cart so that the fasteners may be delivered to a plurality of work stations located throughout a manufacturing facility.
The control system further employs a pneumatic source to remove the fasteners from the fastener storage device and deliver the fasteners through the delivery conduit. Generally, the pneumatic source removes the fasteners from the fastener storage device by activating a vacuum generator that draws a fastener into the unloading mechanism. Once the unloading mechanism is positioned adjacent the delivery conduit, the vacuum generator is deactivated, and the fastener is dropped into the delivery conduit. The pneumatic source is then activated to deliver the fastener to a work station using pressurized air through the delivery conduit.
In operation, the control system receives a request for a particular fastener configuration and positions the unloading mechanism adjacent the fastener storage device where the requested fastener is located. Preferably, the control system comprises a linear X-Y positioner that positions the unloading mechanism during operation of the portable fastener delivery system. The vacuum generator is then activated to remove the fastener from the fastener storage device and into the unloading mechanism. Accordingly, the unloading mechanism is positioned adjacent the delivery conduit using the linear X-Y positioner, and the vacuum generator is deactivated, which causes the fastener to drop into the delivery conduit.
The fastener is partially transported through the delivery conduit by gravity, and then the pneumatic source is activated to provide pressurized air to complete delivery of the fastener to the work station. Accordingly, the delivery conduit further comprises a proximity sensor, wherein when the fastener is transported past the proximity sensor, the proximity sensor notifies the control system, and the control system activates the pneumatic source to provide the pressurized air for delivery of the fastener.
More specifically, the delivery conduit further comprises a drop station having at least one drop plate defining a chute, wherein the fastener is dropped into the chute by the unloading mechanism. The chute is in communication with a fixed fastener delivery tube that is further in communication with a flexible fastener delivery tube, wherein the flexible fastener delivery tube extends from the portable platform to the work station where the fastener is delivered. Accordingly, the fastener is transported through the fixed fastener delivery tube by gravity and is further transported to the work station through the flexible fastener delivery tube by pressurized air from the pneumatic source. Preferably, the proximity sensor is positioned at the end of the fixed fastener delivery tube such that when the fastener passes the proximity sensor, the pneumatic source is activated to deliver the fastener through the flexible fastener delivery tube to the work station. Additionally, the delivery conduit may comprise a plurality of fixed and flexible fastener delivery tubes in order to deliver a variety of fastener types to a plurality of work stations throughout a manufacturing facility.
The fixed fastener delivery tube and the flexible fastener delivery tube are preferably connected using a fitting that comprises two flexible prongs. The fitting is attached to the fixed fastener delivery tube using, for example, welding or adhesive bonding, and the flexible fastener delivery tube is inserted between the two flexible prongs. The inside diameter defined by the flexible prongs is slightly larger than the outside diameter of the flexible fastener delivery tube such that the flexible fastener delivery tube is disposed within the flexible prongs with a clearance fit. To further secure the flexible fastener delivery tube, an adhesive tape is wrapped around the fitting proximate the flexible fastener delivery tube to seal and secure the connection between the fixed fastener delivery tube and the flexible fastener delivery tube. Alternately, other securement methods may be used to secure the flexible fastener delivery tube to the fitting such as a hose clamp, among others known in the art.
The fastener storage device is generally a fastener cassette that comprises a plurality of fastener storage tubes that house the fasteners. Each fastener storage tube houses a specific fastener configuration, which includes the fastener type (i.e. hi-lok, jo-bolt, rivet), diameter, and grip length. Accordingly, the fastener storage tubes range in diameter corresponding to the specific fastener configuration housed therein. Furthermore, the fastener storage device is removable from the portable fastener delivery system to facilitate ease of replacement when additional types of fasteners may be required or when the fastener storage device is moved to an assembly at another work station. Moreover, a plurality of fastener cassettes may be used as necessary within the portable fastener delivery system.
The fastener storage device is also stackable such that a plurality of fastener storage devices may be stored, for example, in a tool crib for use as required throughout a manufacturing facility. Moreover, the fastener storage device is reconfigurable, wherein an upper plate and a lower plate that accommodate the fastener storage tubes are interchangeable to facilitate a variety of fastener configurations. Additionally, the fastener storage tubes may also be interchangeable, wherein fastener tube cartridges that house the fastener storage tubes are removed and replaced depending on particular fastener configuration requirements.
The fasteners are generally removed from the fastener storage tube using the unloading mechanism, which further comprises an extractor tool and an extractor catcher disposed therein. The extractor catcher defines a tapered interior surface with a substantially flat upper inner surface in order to capture and secure a fastener when the vacuum generator is activated as previously described. When the extractor tool is positioned adjacent the appropriate fastener storage tube and the extractor catcher abuts the fastener storage device, the vacuum generator is activated and the entire stack of fasteners is drawn up through the fastener storage tube until the top fastener abuts the substantially flat upper surface of the extractor catcher. Preferably, the extractor tool and the extractor catcher are positioned against the fastener storage device using a vertical axis positioner. When the top fastener abuts the extractor catcher, the vacuum from the vacuum generator is sealed at the interface between the fastener and the extractor catcher, thereby causing the remaining stack of fasteners to drop back down into the fastener storage tube. As a result, a single fastener is removed from the stack of fasteners without the need for a separate escapement mechanism.
Once the fastener is secured within the extractor catcher, the control system positions the unloading mechanism adjacent the delivery conduit, wherein the fastener is delivered using pressurized air from the pneumatic source as previously described. Accordingly, the portable fastener delivery system automatically delivers a variety of different fastener configurations to one or a plurality of work stations, thereby reducing assembly time and the risk of FOD during fastening operations.
The control system that activates the pneumatic source and positions the unloading mechanism is preferably operated using a computing device such as a personal computer or programmable logic controller with control software specifically programmed for delivery of fasteners to a work station. Generally, input to the personal computer is the request for a specific fastener configuration, which may be manually entered using a keyboard or touch screen of the personal computer or transmitted to the control system with an input device such as an electronic grip length checker, a microphone, a computer operated pendant, a bar code reader or other auto identification system, or other device commonly known in the art. Further, the output of the personal computer generally comprises the positions for the unloading mechanism adjacent the appropriate fastener storage tube and adjacent the delivery conduit, along with signals that activate the pneumatic source throughout the delivery process. Additional control system electronics and pneumatics are also activated by the personal computer as further described hereinafter.
The control software comprises a database of fastener configurations, along with a real-time inventory of the fasteners housed within the fastener storage tubes as the fasteners are being delivered to the work station. The database further comprises system parameters and fastener parameters, wherein the system parameters further comprise parameters for the fastener storage device that include, for example, the position of each fastener storage tube, the fastener configuration in each tube, and the current number of fasteners in each tube.
The control software database is preferably coordinated with a master fastener database so that duplication of data is minimized. In addition, the database may be in communication with other inventory systems within a manufacturing environment for more efficient production control. Further, the software may be coordinated with data from a product data manager (PDM), wherein specific engineering call-outs for fasteners in a specific assembly are used by the software to deliver fasteners to the work station. Moreover, fastener data may be used to generate a digital image of an assembly with the position and configuration of each fastener therein. The digital image is preferably presented on a monitor or screen of the personal computer for viewing and interrogation by the operator or other manufacturing personnel.
In operation, the control system receives a request for a specific fastener configuration, which may be through computer entry, e.g., touch screen, keyboard, signal reception from hole measuring device, voice activation, or other methods commonly known in the art. The control system then activates the linear X-Y positioner to position the unloading mechanism adjacent the proper fastener storage tube within the fastener storage device. Once the unloading mechanism is properly positioned, the pneumatic source is activated to position the extractor tool and the extractor catcher down against the fastener storage device using the vertical axis positioner such that the extractor catcher is in communication with the fastener storage tube. The pneumatic source then activates the vacuum generator, and as a result, the entire stack of fasteners within the fastener storage tube is drawn up against the extractor catcher. When the top fastener abuts the flat upper surface of the extractor catcher, the vacuum is sealed at the interface between the top fastener and the extractor catcher, and thus the remaining fasteners fall back down into the fastener storage tube.
Once the extractor catcher acquires the fastener, the linear X-Y positioner positions the unloading mechanism adjacent the drop station, and more specifically, positions the extractor catcher adjacent the appropriate chute. The control system then deactivates the pneumatic source, which deactivates the vacuum generator, and the fastener drops from the extractor catcher through the chute and into the fixed fastener delivery tube. Accordingly, the fastener is transported through the fixed fastener delivery tube by gravity. Once the fastener passes beyond the proximity sensor, the control system activates the pneumatic source once again, which provides pressurized air to the flexible fastener delivery tube to deliver the fastener to the work station. In one form of the present invention, the entire fastener delivery process, from the time of the request for a fastener to the time the fastener arrives at the work station is less than approximately three (3) seconds.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.